In this description, the term “User Equipment” (UE) will be used to denote any suitable communication terminal adapted to communicate with a radio base station. A UE may be implemented as a mobile phone, a PDA (Personal Digital Assistant), a handheld computer, a laptop computer, etc. A “radio base station” may be implemented as a NodeB, an eNodeB, a repeater, etc.
Even if the radio base stations often have their own respective connections to the backhaul network, they are commonly capable to communicate data via any other radio base station(s) to a backhaul network and the core network. “Backhauling” is a term which is used to denote that a radio base station establishes an association to the core network possibly via one or more base stations and a backhaul network.
“Routing” is a process where a communication network calculates how to forward packets between devices connected to this network. Typically, this is done as follows: Neighbours connected to one another will exchange identities. This information will be flooded throughout the network to all other nodes. Each node will then calculate its own routing, so that eventually all nodes in the network know how to route packets in the network. A radio base station which has been discovering another radio base station via the backhaul links connecting both to one another determines an IP-address of the discovered radio base station, e.g. by pinging possible IP-addresses. By applying the IP-address it connects to the discovered radio base station by applying a routing protocol to setting up a route to the discovered radio base station. After routing, the discovering routing radio base station will be able to transmit and receive communication data with the discovered radio base station.
A backhaul network is an intermediate network arranged to distribute communication of data between radio base stations and a core network. Typically, backhauling networks comprise communication network nodes as radio network controllers, etc.
With reference to FIG. 1, which is a schematic environmental overview, a scenario where communication two radio base stations 102, 104 routes a backhaul link between one another will now be described.
In a radio access network 100 a plurality of radio base stations 102, 104 are arranged to communicate data with a core network 130 via a backhaul network 120. Generally, all radio base stations do not necessarily have their own dedicated connections 122 to a backhaul network 120, and thereby to the core network 130. The radio base stations 102, 104 are instead, typically, connected to the backhaul network 120 via each other. This is particularly true for indoor solutions, but is also very common in currently deployed outdoor macro RBS solutions. Such connections 106 are physical connections, capable to convey control data, e.g. fibres, wireless links, or cables. However, the radio base stations 102, 104 are not able to communicate communication data on these physical connections 106 before a backhaul link is routed, as described above.
Mobile backhauling, be it for small cells or macro cells, rely on two key technologies to operate, namely packet forwarding protocols for communication data between radio base stations on backhaul links, and routing protocols for exchanging routing information when establishing the backhaul links.
Some examples of Packet forwarding protocols are: Ethernet, IP (Internet Protocol) or MPLS (Multi-Protocol Label Switching), or combinations of them. Examples of routing protocols which enables routers/switches to exchange routing information with one another are: Ethernet Tree-Spanning, OSPF (Open Shortest Path First), RIP (Routing Information Protocol), IS-IS (Intermediate-System to Intermediate-System), BGP4 (Border Gateway Protocol 4). Depending on needs or operator strategies, different networks often deploy different technologies, e.g. some will prefer Ethernet based backhaul, whilst others will prefer MPLS.
There are numbers of reasons beyond selections of protocols/technologies, e.g. security, network management, and MBH (Mobile BackHaul) network deployment.
There is a need to effectively and flexible manage establishing backhaul links in radio access network, without increasing the amount of signalling information.